X-ray Images of Sagittarius A*
Researchers have found evidence that the normally dim region very close to the supermassive black hole at the center of the Milky Way galaxy flared up with at least two bright outbursts in the past few hundred years. These images are from a study of Chandra observations taken over twelve years that show rapid variations in the X-ray emission from gas clouds surrounding the supermassive black hole. The phenomenon, known as a "light echo," provides astronomers an opportunity to piece together what objects like Sgr A* were doing long before there were X-ray telescopes to observe them.
(Credit: NASA/CXC/APC/Université Paris Diderot/M.Clavel et al)